Modular insulation system

ABSTRACT

A method for isolating phases in an electrical equipment enclosure having multi-phase bus bars and a mounting base for mounting electrical equipment. The insulation system includes a plurality of components including a plurality of side isolation barriers with each barrier defining at least one slot proximate one edge of the barrier and having at least one tab along another edge of the barrier. A side barrier adapter is configured to engage the isolation barrier and to engage the mounting base. An inner isolation barrier is configured to isolate at least two of the vertical bus bars and couple to the mounting base. A vertical bus rear wall defining a plurality of slots proximate at least two edges of the cover is fastened to the inner isolation barrier. A plurality of corner connectors is configured to engage one of the cover slots and the side isolation barrier slots.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a Divisional of U.S. application Ser. No.11/007,665, filed Dec. 8, 2004, incorporated herein by reference in itsentirety.

FIELD

The present disclosure relates generally to the field of electricalswitchboards and panel boards and more particularly to a modularinsulation system for bus bars in switchboard and panel boardenclosures.

BACKGROUND

Switchgear assemblies and switchboards and panel boards are generalterms which cover metal enclosures, housing switching and interruptingdevices such as fuses and circuit breakers, along with associatedcontrol, instrumentation and metering devices. Such assemblies typicallyinclude associated bus bars, interconnections and supporting structuresused for the distribution of electrical power. Low voltage switchgearand switchboards operate at voltages of up to 600 volts and withcontinuous currents up to 5000 amps or higher. Such devices are alsodesigned to withstand short circuit currents ranging up to 200,000 amps(3 phase RMS symmetrical).

Typical switchgear equipment is composed of a lineup of several metaland closed sections. Each section may have several circuit breakersstacked one above the other vertically in the front of the section witheach breaker being enclosed in its own metal compartment. Each sectionhas a vertical or section bus which supplies current to the breakerswithin the section by short horizontal branch busses, also referred toas run-in busses. The vertical bus bars in each section are suppliedwith current by a horizontal main bus bar that runs through the lineupof metal enclosed sections. The vertical bus bars may be configured asseparate individual sections that require isolation from each othervertically as well as horizontally. A typical arrangement includes busbars for each electrical phase of a multi-phase system which may includethree power phases and a neutral.

In multi-phase systems, it is desirable to isolate the bus bars of eachphase from each other and the other components in the enclosure.Isolation is beneficial to minimize hazards to personnel and to reducearc fault hazards. Since configuration of switchboard enclosures andequipment vary from application and installation, a modular standardinsulation system is easier to configure and install.

Thus there is a need for a modular insulation system for an electricalequipment enclosure having multi-phase vertical and horizontal bus bars.There is a further need to have an isolation system that can be easilyconfigured, maintained, and installed without special tools and with aminimum of tools.

SUMMARY

There is provided a method for isolating phases in an electricalequipment enclosure having vertical bus bars and a mounting base formounting electrical equipment. The method includes the steps ofproviding a plurality of side isolation barriers. A side barrier adapteris provided. Coupling the side barrier adapter to the mounting base andat least one side isolation barrier. An inner isolation barrier isprovided. Coupling the inner isolation barrier to the mounting base toisolate at least two of the vertical bus bars from each other. Avertical bus rear wall is provided. A plurality of corner connectors areprovided. Coupling the vertical bus rearwall and at least one sideisolation barrier to at least one corner connector, wherein the verticalbus bars are individually isolated from each other. Another embodimentof the method of isolating phases includes the step of configuring thevertical bus rearwall with an opening for each runback bus bar. Themethods may also include the step of providing an insulation shroud andcoupling the insulation shroud to each runback bus bar.

There is further provided a modular insulation system kit for isolatingphases in an electrical equipment enclosure with a modular insulationsystem. The enclosure includes a plurality of vertical bus bars and amounting base for mounting electrical equipment. The kit includes a sidebarrier adaptor configured to couple to the mounting base and at leastone side isolation barrier. An inner isolation barrier is configured tocouple to the mounting base to isolate at least two of the vertical busbars from each other. A vertical bus rear wall and at least one sideisolation barrier are each configured to couple to at least one cornerconnector, wherein the vertical bus bars are individually isolated fromeach other.

There is further provided an electric equipment enclosure which includesa plurality of vertical bus bars coupled to the enclosure, with at leastone vertical bus bar configured for each of an electrical phase. Ahorizontal bus bar is coupled to the at least one vertical bus bar foreach electrical phase. A mounting base is coupled to the enclosure andconfigured to receive electrical equipment. A modular insulation systemis configured to isolate the vertical bus bars of each electrical phase,The modular insulation system comprises a side barrier adapter coupledto the mounting base and at least one side isolation barrier. An innerisolation barrier is coupled to the mounting base and configured toisolate at least two vertical bus bars from each other. A vertical busrear wall is coupled to at least one side isolation barrier with at lastone corner connector, wherein the vertical bus bars are individuallyisolated from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrical equipment enclosureincluding compartments for electrical equipment, such as circuitbreakers and including an exemplary embodiment of a modular insulationsystem.

FIG. 2 is a perspective view of an electrical equipment enclosure fromthe rear aspect, including an exemplary embodiment of a multiple phase,vertical bus bars, with each vertical bus bar having three sectionsseparated by a split bus barrier.

FIG. 3 is an exemplary embodiment of a mounting base for electricalequipment including a side barrier adapter and side isolation barrier ofa modular insulation system on each of the two ends of the mountingbase.

FIG. 4 is an exemplary embodiment of a mounting base for electricalequipment and including two inner isolation barriers of a modularinsulation system configured to isolate bus bars in adjacent electricalphases.

FIG. 5 illustrates two views of an exemplary embodiment of a sidebarrier adapter for a modular insulation system.

FIG. 6 is a plan view of an exemplary embodiment of a side isolationbarrier of a modular insulation system.

FIG. 7 is a perspective view of an exemplary embodiment of a cornerconnector of a modular insulation system.

FIG. 8 illustrates several views of an exemplary embodiment of an innerisolation barrier of a modular insulation system.

FIG. 9 is a perspective view of an exemplary embodiment of a split busbarrier of a modular insulation system defining two slots configured tointerlock with the inner isolation barrier of the modular insulationsystem.

FIG. 10 a is a perspective view of an exemplary embodiment of a mountingbase with multiple phase runback bus bars extending through orificesdefined in the mounting base with the runback bus bars partially encasedin an insulation shroud of a modular insulation system.

FIG. 10 b is a perspective view of one of the insulation shroudsillustrated in FIG. 10 a.

FIG. 11 is a perspective view of an exemplary embodiment of anelectrical equipment enclosure including a modular insulation systemisolating the vertical bus bars from each other and illustrating severalexemplary embodiments of a vertical bus rearwall having differentlyconfigured openings for bus bars, bus braces and ventilationarrangements

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Before describing the exemplary embodiments of a modular insulationsystem for electrical equipment in an electrical equipment enclosure,for example, an electrical equipment enclosure, several comments areappropriate. Switchgear assemblies and panel board assemblies typicallyinclude vertical (section) bus bars to distribute electrical powerwithin the enclosures. In a short circuit condition, extreme magneticforces are created in the bus bars as a result of short circuit currentsup to and including 200,000 amps symmetrical RMS flowing through eachbus bar. In a three phase power system (typically) as a short circuitcurrent flows through such bus bars, magnetic forces between adjacentbus bars tend to move such bus bars laterally (perpendicular) to thecurrent flow. Such movement of the bus bars is typically prohibited orinhibited to avoid damage in arcing within an electrical equipmentenclosures by bus bar brace apparatus and equipment arrangements withinan electrical equipment cabinet. However, it is still expedient toprovide isolation of the bus bars in each phase to further minimize arcflash and potential short circuit conditions. The modular insulationsystem that will isolate the bus bars from each other (and allow theenclosure designer or the maintenance of the enclosure) easier toconfigure and also easier to manufacture since standard components canbe prepared and used for a variety of installation configurations. Amodular insulation system kit including the several components describedherein may also be provided in the field.

An additional advantage to use of the modular insulation system toisolate the bus bars within the several phases of the electricalequipment enclosure is the isolated phase vertical bus bars exhibitimproved convection cooling which increases their continuous currentcapability. The bus bars can still be braced for short circuitconditions with the bus base brace apparatus without blocking air flowaround or between the bus bar members. This “chimney effect” is alsofacilitated if the bus bars have a C-channel shape. Also, if twoC-channel shape bus bars are aligned with their short sidewalls of eachC-shaped bus bar facing each other, a spaced apart rectangular tube isformed which further facilitates air movement and thus cooling of thebus bar system. An example of such C-channel shaped bus bar is disclosedin U.S. patent application entitled ELECTRIC BUS BAR filed Dec. 8, 2004(Ser. No. 11/007,664, now abandoned) and assigned to the assignee of thepresent application.

Referring now to the figures, FIG. 1 is an illustration of exemplaryembodiment of an electrical equipment enclosure 10, without several ofthe outer panels for clarity purposes. FIG. 1 also illustrateselectrical equipment compartments for circuit breakers in theillustrated drawing mounted in the front of an electrical equipmentcabinet 10. A mounting base, 22 (not shown in FIG. 1) forms the rearwall of the equipment compartment CB and is coupled to several of theframe members 12 of an electrical equipment enclosure 10.

FIG. 1 specifically depicts a multi-phase switchgear assemblyconventionally having three power phases, A B and C. A neutral bus orgrounding bus can also be provided. In the illustration of FIG. 1,horizontal bus bars 18 feed the main electrical power to the enclosure10 and to adjacent enclosures (not shown) in a typical installation.

FIG. 2 illustrates vertical bus bars 14 extended typically throughoutthe height of an electrical equipment enclosure 10 with horizontal busbars 18 selectively positioned and connected mechanically andelectrically to the vertical bus bars 14 for the distribution of powerwithin the system. Spaced apart frame members 12 are mounted within anelectrical equipment enclosure 10 at predetermined positions to supportelectrical equipment such as circuit breakers mounted in the enclosure10. The equipment can be accessed from either the front side 13 or theback side 11 of the enclosure 10. An example of a typical electricalequipment that is mounted in an electrical equipment enclosure 10 is acircuit breaker CB. A circuit breaker mechanism is typically containedwithin a housing. The housing is coupled to a mounting base 22 whichsupports the circuit breaker housing and provides an apparatus forcoupling the circuit breaker to the various bus bars within anelectrical equipment enclosure 10. A mounting plate system is used toattach the base member 22 to the frame members 12 of an electricalequipment enclosure 10.

FIGS. 3-11 illustrate an exemplary embodiment of a modular insulationsystem for electrical equipment in an electrical equipment enclosure 10.

Side isolation barriers 32 are configured in a planar arrangement havingat least one edge 34 and another edge 36 used for attaching the sideisolation barrier 32 to other components of the insulation system 30. Atleast one slot 38 proximate one edge 34 of the barrier is defined in theside isolation barrier 32 and having at least one tab 40 defined alonganother edge 36 of the barrier 32.

The side isolation barrier 32 is coupled to the mounting base 22 with aside barrier adapter 42. (See FIGS. 3, 5 and 6.) The side barrieradapter 42 is configured with at least one snap lug 44 and also definesadapter slots 43 in each of the walls forming the side barrier adapter42. The snap lugs 44 engage slots defined in the mounting base 22 andthe tabs 40 formed on the side isolation barriers 32 engage the adapterslots 43 in the side barrier adapter 42. A typical arrangement is tohave a side barrier adapter 42 and side isolation barrier 32 coupled totwo sides (typically the narrower side) of the mounting base 22. Asillustrated in FIGS. 1 and 2, several side mounting barriers 32 arearranged vertically to isolate the vertical bus bars 14 in theenclosure. The side isolation barrier 32 can be fabricated from a flatsheet of insulating material and cut to size as is necessary to fitwithin an electrical enclosure 10.

FIGS. 4 and 8 illustrate inner isolation barriers 46 configured toisolate at least two of the vertical bus bars 14 and coupled to themounting base 22. The inner isolation barrier 46 is secured to themounting base 22 by a fastener such as a screw or a bolt or a rivet. InFIG. 4, two inner isolation barriers 46 are shown with the mounting base22. FIG. 8 illustrates several views of an inner isolation barrier 46 toshow different configurations, for example, one inner isolation barrier46 is not configured with slots whereas another inner isolation barrier46 includes a slot to facilitate the mounting of a split bus barrier 70.FIG. 2 illustrates a plurality of inner isolation barriers 46 mountedbetween the phases of the multiple phase vertical bus bars 14 in anelectrical equipment enclosure 10.

To complete the enclosure of the vertical bus bars 14, in the enclosure10, the vertical bus rearwall 50 is configured to extend across thewidth of the enclosure and couple to the side isolation barriers 32 asillustrated in FIG. 11. A plurality of corner connectors 60 are providedto couple the vertical bus rearwall 50 with the side isolation barriers32. The corner connectors are configured with two walls 62, 64 and thatare aligned at a 90° angle with each wall and configured to engage oneof the cover slots 56 and the side isolation barrier slots 38. (See FIG.7 which is a perspective view of a corner slot 60.) The vertical busrearwall 50 defines a plurality of slots 56 approximate at least twoedges 52, 54 of the cover 50. The vertical bus rearwall 50 is alsofastened to the inner isolation barrier 46 with fasteners such as screwsor the like.

The vertical bus rearwall 50 can be configured with a variety ofopenings 58 to accommodate various bus bar, bus brace and ventilationarrangements. FIG. 11 illustrates three exemplary embodiments of avertical bus rearwall 50 having various ventilating openings and bus baropenings. Connecting bus bars (not shown) extend through such openings58 in the vertical bus rearwall 50 and couple the vertical bus bars 14(See FIG. 2) to selective horizontal bus bars 18 (See FIG. 1).

The runback bus bars 19 typically extend through the mounting base 22and couple the circuit breaker disconnects (not shown) to, for example,the cable terminals (not shown). FIG. 10 a illustrates a typicalarrangement of three runback bus bars 19 (one for each phase) extendingthrough a mounting base 22. The runback bus bars 19 include aninsulation shroud 68 which is a component of the modular insulationsystem 30. FIG. 10 b illustrates an exemplary embodiment of an isolationshroud 68 for use with a runback bus bar 19.

In some installations, the vertical bus bars 14 are separatedvertically. The separate sections of the vertical bus bars 14 alsorequire isolation between the vertical sections of the vertical bus bar14. (Such vertical bus sections are referred to as a split bus bar.)FIG. 9 illustrates an exemplary embodiment of a split bus barrier 70which isolates at least two sections of the vertical bus bar 14. FIG. 2includes two split bus barriers 70 mounted between sections of thevertical bus bar 14 in each phase of the electrical distribution systemwithin the enclosure 10.

The side isolation barrier 32, side barrier adapter 42, inner isolationbarrier 46, vertical bus rearwall and the corner connectors 60 can becomposed of a thermoplastic material. In some installations, thecomponents can be composed of a thermal plastic that is a clearpolycarbonate to allow viewing of the vertical bus bars 14 and interconnections. The vertical bus rearwalls 50 and the side isolationbarriers 32 can also be fabricated from glass reinforced polyester sheetmaterial, for example, GPO-2.

With the several modular insulation system 30 components installed, thevertical bus bars 14 are isolated both phase-to-phase andphase-to-ground. The back side of the mounting base 22 forms the frontwall of the vertical bus compartment. The side isolation barriers 32 andthe side barrier adapters coupled to the mounting base 22 form theoutside sidewalls of the vertical bus compartment. The vertical busrearwall 50 creates the rear wall and the inner isolation barriers 46provide the internal phase isolation. Each phase, of the vertical bus14, is thereby enclosed in a separate, insulated vertical enclosure thatcreates an unobstructed vertical air duct or chimney to provideconvection cooling for the vertical bus 14. In the configurations wherethe vertical bus 14 is divided into two or more sections, a split busbarrier 70 is installed. In such case, the vertical bus rear wall 50provides orifices 58 for ventilation to allow air to enter and exitabove and below the split bus barrier 70 to preserve the chimney effect.In some installations, a vertical brace insulation covers 71 can beprovided, as illustrated in FIG. 11.

One advantage of the modular insulation system 30 is that the only toolrequired to assemble or disassemble selected modular insulation systemcomponents is a screwdriver. Another advantage of the modular insulationsystem 30 is that repairs and maintenance of the various components canbe accomplished from the rear side of the enclosure 10 withoutdisassembling other components within the enclosure 10.

For purposes of this disclosure, the term “coupled” means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents or the two components and any additional member beingattached to one another. Such joining may be permanent in nature oralternatively may be removable or releasable in nature

Thus, there is provided a modular system to insulate and isolate phaseto phase vertical bus bars in an electrical equipment enclosure. Theforegoing description of embodiments have been presented for purposes ofillustration and description. It is not intended to be exhaustive nor tobe limited to the precise forms disclosed and modifications andvariations are possible in light of the above teachings or may beacquired by practice of the invention. The embodiments are chosen anddescribed in order to explain the principles and practical applicationto enable one skilled in the art to utilize the modular insulationsystem in various embodiments and with various modifications that aresuited to the particular use contemplated. It is intended that the scopeof the modular insulation system be defined by the claims appendedhereto and their equivalents.

1. A method for isolating phases in an electrical equipment enclosure having vertical bus bars and a mounting base for mounting electrical equipment, the method comprising the steps of: providing a plurality of side isolation barriers; providing a side barrier adaptor; coupling the side barrier adaptor to the mounting base and at least one side isolation barrier; providing an inner isolation barrier, coupling the inner isolation barrier to the mounting base to isolate at least two of the vertical bus bars from each other; providing a vertical bus rear wall, providing a plurality of corner connectors; and coupling the vertical bus rear wall and at least one side isolation barrier to at least one corner connector, wherein the vertical bus bars are individually isolated from each other.
 2. The method of claim 1, including the step of configuring the vertical bus rear wall with an opening for a runback bus bar.
 3. The method of claim 2, including the steps of providing insulation shrouds and coupling the insulation shrouds to the runback bus bars.
 4. The method of claim 1, including the step of installing a split bus barrier between sections of the vertical bus bar.
 5. The method of claim 1, wherein the side isolation barrier, side barrier adaptor, inner isolation barrier, vertical bus rear wall, and corner connectors are composed of one of thermoplastic and thermoset material.
 6. The method of claim 5, wherein the thermoplastic is a clear polycarbonate.
 7. The method of claim 4, wherein the split bus barrier is composed of one of thermoplastic and thermoset material.
 8. The method of claim 1, including the step of only using a screw driver to assemble and disassemble selective modular insulation system components.
 9. A modular insulation system kit for isolating phases in an electrical equipment enclosure, the enclosure including a plurality of vertical bus bars and a mounting base for mounting electrical equipment, the kit comprising: a side barrier adaptor configured to couple to the mounting base and at least one side isolation barrier; an inner isolation barrier configured to couple to the mounting base to isolate at least two of the vertical bus bars from each other; and a vertical bus rear wall and at least one side isolation barrier each configured to couple to at least one corner connector, wherein the vertical bus bars are individually isolated from each other.
 10. The kit of claim 9, wherein the vertical bus rear wall defines an opening for a runback bus bar coupled to a vertical bus bar.
 11. The kit of claim 10, including insulation shrouds configured to couple to the runback bus bars.
 12. The kit of claim 9, including a split bus barrier configured to isolate sections of the vertical bus bar.
 13. The kit of claim 9, wherein the side isolation barrier, side barrier adaptor, inner isolation barrier, vertical bus rear wall, and the corner connector are composed of one of thermoplastic and thermoset material.
 14. The kit of claim 13, wherein the thermoplastic is a clear polycarbonate.
 15. The kit of claim 12, wherein the split bus barrier is composed of one of thermoplastic and thermoset material.
 16. The kit of claim 9, including a screw driver to assemble and disassemble selective modular insulation system kit components.
 17. An electric equipment enclosure comprising: a plurality of vertical bus bars coupled to the enclosure, with at least one vertical bus bar configured for each of an electrical phase; a horizontal bus bar coupled to the at least one vertical bus bar for each electrical phase; a mounting base coupled to the enclosure and configured to receive electrical equipment; and a modular insulation system configured to isolate the vertical bus bars of each electrical phase, the modular insulation system comprising: a side barrier adapter coupled to the mounting base and at least one side isolation barrier; an inner isolation barrier coupled to the mounting base and configured to isolate at least two vertical bus bars from each other; and a vertical bus rear wall coupled to at least one side isolation barrier with at last one corner connector, wherein the vertical bus bars are individually isolated from each other.
 18. The electrical equipment enclosure of claim 17, wherein the vertical bus rear wall defines an opening for the horizontal bus bars.
 19. The electrical equipment enclosure of claim 17, including an insulation shroud configured to couple to the horizontal bus bar.
 20. The electrical equipment enclosure of claim 18, wherein the side isolation barrier, side barrier adaptor, inner isolation barrier, vertical bus rear wall, and the corner connector are composed of one of thermoplastic and thermoset material. 